The goal of this project is to design and test an intervention to reduce sexual and injection practice risk behaviors among 1,200 HIV-infected men and women in order to decrease the likelihood that persons with HIV will transmit infection to others and to promote other health-related behavior changes in PLH. The research will be focused on three HIV+ subgroups: women, men who have sex with men (MSM), and injection drug users (IDUs). The study will be undertaken at four sites: Los Angeles, New York, San Francisco, and Milwaukee. The project will begin with a one-year period of formative Phase I studies conducted with 150 PLH (30 per site) using qualitative and life-history interviews to characterize the physical, social, and interpersonal contexts that influence risk behavior among PLH; understand stages of adaptation to serostatus; and identify barriers to implementation of safer sex, positive health care acts, and quality of life. The formative research phase will also allow us to tailor the social action theoretical model guiding the intervention to address issues affecting each subpopulation. Following the formative research phase, a manual will be prepared for an intervention of 15 individually-delivered sessions organized into three modules with components that target health promotion, transmission risk reduction, and psychological coping/relationship issues. In the Phase 2 main intervention trial, three subgroups of HIV-infected persons who have recently engaged in high-risk behavior will be recruited in equal numbers at each site yielding study-wide samples of HIV+ women (N=400), MSM (N=400), and IDUs (N=400). Altogether, 1,200 PLHs project-wide will be randomly assigned in equal numbers within each subgroup to an immediate intervention condition or to a lagged intervention control condition. Following two baseline interviews, participants will be evaluated at 5-month intervals for the next 35 months. In addition to anticipating changes in the primary (transmission risk acts) and secondary (health care behaviors and quality of life) outcomes over time and in response to each module, we will examine the impact of mediating factors emerging from social action theory (coping skills, social support, problem solving, HIV-related attitudes/beliefs, and environmental context of risk acts), as well as participant background factors (gender, ethnicity, history of transmission behaviors) on primary and secondary outcomes. The study will be implemented by a consortium of four sites in order to provide sufficient sample sizes to assess the impact of the intervention; to enhance generalizability of the findings; and to utilize the specialized expertise of each research team. Cost-effectiveness analyses, and dissemination are planned as part of this study.